The Damaging Effects Of Sediment Erosion And Deposition On The Bank And Building Study

Bank failure is the result of the interaction of water flow and the bank, a widespread natural phenomenon. Reservoir bank failure is a typical form of collapse. It is the horizontal evolution of the bank, and the one of the problem of bank stability. This is a typically cross-cutting issues. The mechanism of reservoir bank failure is very complicated, the main factors of impact such as current conditions, river erosion and deposition and the geological characteristic of the soil. This essay mainly researches the bank failure caused by the erosion and sedimentation.The movement of water and sediment in the reservoir belongs to the 3-D turbulence flow state, which is so complex that to setting up the mathematics model of it will need some workload. To choose the model suit for the situation, many researching result of the former researchers is discussed and used for reference in the essay ,and at last the k-e model combined with Eulerian model is choused to do the numerical simulation work. The control equations of 3-D water and sediment movement are described in the orthogonal curvilinear coordinates and the equations is segregated by using the Finite Volume Method (FVM). The SIMPELC algorithm was adopted in the numerical program. At last, to solve the dispersed equations Gauss-Seidle method is used.In order to explore the movement of the reservoir water and sediment, and in different conditions of inflow and sediment, the interrelationship of water and sediment conditions and the different forms of reservoir sedimentation, and revealed the mechanism of the reservoir bank failure, a physical model was established, according to the reservoir bank failure factors and the purpose of this study. And multiple tests were conducted. To verify the accuracy of mathematical models and to explore movement of the reservoir water and sediment, a numerical calculation was done. Results of physical model and the calculation shows that this mathematics model can simulate the movement of the water and sediment in the reservoir very well at a certain extent, based on the appropriate assumptions and simplified. Some conclusions can drew from the study: the form of sedimentation changes with conditions of flow and sediment, while the models are the same. The sedimentation is apt to form before dam when the velocity of flow is large and the grains size is small, and it is banding form that can arouse middle eroding and side silting. This kind of form contributes to reservoir bank stabilization. But in the other hand, the sedimentation is apt to form in head of reservoir when the velocity of flow is small and the grains size is large, and it is a delta form that can arouse side eroding and middle silting. This kind of form tends to arouse reservoir bank's unsteadiness.Based on the results of numerical simulation models and physical tests, the mathematical models were used in for the projects:①Heihe hinge. The results of calculation are matched the realistic situation better, and some measures of the sediment rectification were gave, base on the calculation results.②Shangdong electric power station. The results show that the left bank of the river was washed serious by water and it needs the floodwalls to protect the bank.